System and method for integrated waste storage

ABSTRACT

The present invention provides integrated bunker storage systems for waste streams based on the composition and characteristics of waste stream. In particular, the present invention provides a process for generating individual waste streams based on a set of material characteristics. According to the system and method of the present invention, individual waste streams from wastes stored in bunkers are mixed in a given feed ratio to generate a food stock that will produce a desired output from a chemical conversion process, e.g., gasification. Optionally, composition data regarding the fed stock can be certified to a third party.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit under 35 U.S.C. §120U.S. as a continuation of U.S. non-provisional application Ser. No.12/491,650, filed Jun. 25, 2009, entitled “System and Method forIntegrated Waste Storage,” now U.S. Pat. No. 9,217,188, which claimspriority to and the benefit under 35 U.S.C. §119(e) of U.S. ProvisionalPatent Application No. 61/075,988, filed on Jun. 26, 2008, entitledSystem And Method For Integrated Waste Storage, all of which are hereinincorporated by reference in their entireties.

FIELD OF THE INVENTION

The present invention generally relates to alternative energy, fuels,and petrochemicals. More particularly, the present invention isconcerned with the recovery of energy and/or raw materials from wastematerials stored in an integrated bunker storage system, and provides aprocess for generating feed stock from the waste streams for optimumconversion to energy, fuel, or petrochemicals.

BACKGROUND OF THE INVENTION

Sources of fuel useful for heating, transportation, and the productionof petrochemicals are becoming increasingly scarce and therefore morecostly. Industries such as those producing energy and petrochemicals areactively searching for cost effective fuel feed stock alternatives foruse in generating those products and many others. Additionally, due tothe ever increasing costs of fossil fuels, transportation costs formoving fuel feed stocks for production of energy and petrochemicals israpidly escalating.

These energy and petrochemical producing industries, and others,normally have relied on the use of fossil fuels, such as coal, oiland/or natural gas, for use in combustion and gasification processes forthe production of energy for heating and electricity, and the generationof synthesis gas used for the downstream production of petrochemicalsand liquid fuels.

Combustion and gasification are thermochemical processes that are usedto release the energy stored within the fuel source. Combustion takesplace in a reactor in the presence of excess air, or an excess ofoxygen. Combustion is generally used for generating steam which in turnis used to generate electricity through steam turbines. However, thebrute force nature of complete combustion of fuel causes significantamounts of pollutants to be generated in the gas given off duringcombustion. For example, combustion in an oxidizing atmosphere of, forexample, coal releases nitrogen oxides, a precursor to ground levelozone which can stimulate asthma attacks. Combustion of high sulfurcontaining fossil fuels, such as coal, is also the largest source ofsulfur dioxide which in turn produces sulfates that are very fineparticulates. Fine particle pollution from U.S. power plants cuts shortthe lives of over 30,000 people each year. Hundreds of thousands ofAmericans suffer from asthma attacks, cardiac problems and upper andlower respiratory problems associated with fine particles from powerplants.

Gasification also takes place in a reactor, although in the absence ofair, or in the presence of substochiometric amounts of oxygen. Thethermochemical reactions that take place in the absence of oxygen orunder substochiometric amounts of oxygen do not result in the formationof nitrogen oxides or sulfur oxides.

Gasification generates a gaseous fuel rich product. During gasification,two processes take place that convert the fuel source into a useablefuel gas. In the first stage, pyrolysis or flaming pyrolysis, the feedstock releases volatile components of the fuel at temperatures below600° C. (1112° F.); a process known as devolatization. The by-product ofpyrolysis that is not vaporized is called char and consists mainly offixed carbon and ash. In the second gasification stage, the carbonremaining after pyrolysis undergoes a reduction processes by reactingeither with steam and/or hydrogen. Gasification with pure oxygen resultsin a high quality mixture of carbon monoxide and hydrogen and virtuallyno nitrogen.

The basic gasification reactions that occur are:

-   -   1) C+1/2O₂→CO −110.5 kJ/mol (exothermic)    -   2) C+H₂O→CO+H₂ +131 kJ/mol (endothermic)    -   3) C+CO₂→2CO +172 kJ/mol (endothermic)    -   4) C+2H₂→CH₄ −74 kJ/mol (exothermic)    -   5) CO+→CO₂+H₂ −41 kJ/mol (exothermic) H₂O    -   6) CO+3H₂→CH₄+H₂0 −205 kJ/mol (exothermic)

All of these reactions are reversible and their rates depend on thereaction kinetics, which are functions of temperature, pressure andconcentration reactants in the reactor. Heat can be supplied directly orindirectly to satisfy the requirements of the endothermic reactions.

A variety of gasifier types have been developed. They can be groupedinto four major classifications: fixed-bed updraft, fixed-bed downdraft,bubbling fluidized-bed and circulating fluidized bed. Differentiation isbased on the means of supporting the fuel source in the reactor vessel,the direction of flow of both the fuel and oxidant, and the way heat issupplied to the reactor.

The updraft gasifier, also known as counterflow gasification, is theoldest and simplest form of gasifier; it is still used for coalgasification. The fuel is introduced at the top of the reactor, and agrate at the bottom of the reactor supports the reacting bed. Theoxidant in the form of air or oxygen and/or steam are introduced belowthe grate and flow up through the bed of fuel and char. In an idealgasifier, complete conversion of char would occur at the bottom of thebed, liberating CO₂ and H₂O. These hot gases (˜1000° C.) pass throughthe bed above, where they are reduced to H₂ and CO and cooled to 750° C.Continuing up the reactor, the reducing gases (H₂ and CO) pyrolyse thedescending dry fuel and finally dry any incoming wet fuel, leaving thereactor at a low temperature (˜500° C.). The advantages of updraftgasification are: simple, higher thermal efficiency, low cost processthat is able to handle fuel with a high moisture and high inorganiccontent. The primary disadvantage of updraft gasification is that thesynthesis gas contains 10-20% tar by weight, requiring extensive syngascleanup before engine, turbine or synthesis applications.

The downdraft gasification, also known as cocurrent-flow gasification,has the same mechanical configuration as the updraft gasifier exceptthat the oxidant and product gases flow down the reactor, in the samedirection as the fuel. A major difference is that this process can crackup to 99.9% of the tars formed. Low moisture fuel (<20%) and air oroxygen are ignited in the reaction zone at the top of the reactor. Theflame generates pyrolysis gas/vapor, which burns intensely leaving 5 to15% char and hot gas. These gases flow downward and react with the charat 800 to 1200° C., generating more CO and H₂ while being cooled tobelow 800° C. Finally, unconverted char and ash pass through the bottomof the grate and are sent to disposal. The advantages of downdraftgasification are: up to 99.9% of the tar formed is consumed, requiringminimal or no tar cleanup Minerals remain with the char/ash, reducingthe need for a cyclone. The disadvantages of downdraft gasification are:requires feed drying to a low moisture content (<20%). The syngasexiting the reactor is at high temperature, requiring a secondary heatrecovery system; and 4-7% of the carbon remains unconverted.

The bubbling fluidized bed consists of fine, inert particles of sand oralumina, which have been selected for size, density, and thermalcharacteristics. As gas (oxygen, air or steam) is forced through the bedof particles, a point is reached when the frictional force between theparticles and the gas counterbalances the weight of the solids. At thisgas velocity (called minimum fluidization velocity), bubbling andchanneling of gas through the media may occur, such that the particlesremain in the reactor and appear to be in a “boiling state”. Thefluidized particles tend to break up the biomass fed to the bed andensure good heat transfer throughout the reactor. The advantages ofbubbling fluidized-bed gasification are: yields a uniform product gas;exhibits a nearly uniform temperature distribution throughout thereactor; able to accept a wide range of fuel particle sizes, includingfines; provides high rates of heat transfer between inert material, fueland gas; high conversion possible with low tar and unconverted carbon.The disadvantages of bubbling fluidized-bed gasification are: lowergas-solid contact efficiency due to formation of bubbles, and increasedattrition and dust entrainment rates. large bubble size may result ingas bypass through the bed.

The circulating fluidized bed gasifiers operate at gas velocities higherthan the so-called transport velocity, resulting in significantentrainment of the particles in the gas stream. Thus the entrainedparticles in the gas exited from the top of the reactor mustbe—separated in a cyclone and returned to the reactor. The advantages ofcirculating fluidized-bed gasification are: it is suitable for rapidreactions; high heat transport rates possible due to high heat capacityof bed material; high conversion rates possible with low tar andunconverted carbon. It also makes production of higher energy contentsyngas possible because heat required for gasification can betransferred from outside through circulating particles acting as heatcarriers. The disadvantages of circulating fluidized-bed gasificationare: temperature gradients occur in the direction of solid flow; smallerparticles are required; high velocities may result in equipment erosion;and heat exchange is less efficient than bubbling fluidized-bed.

Normally these gasifiers use a homogeneous source of fuel because aconstant unchanging fuel source allows the gasifier to be designedoptimally for this particular fuel, for production of a desired product.Common types of fuel used today in gasifiers are wood, coal, petroleum,and, biomass. Since some of these fuel sources are becoming increasinglymore expensive, energy and petrochemical suppliers are seekingalternative fuel feed stocks.

One potential source of a large amount of feed stock for gasification iswaste. Waste such as municipal solid waste is presently often disposedof or used in incineration processes to generate heat and/or steam foruse in—turbines. Incineration is a combustion process and the negativedrawbacks for combustion have been described above.

One of the most significant threats facing the environment today is therelease of greenhouse gases (GHGs) into the atmosphere. GHGs such ascarbon dioxide, methane, nitrous oxide, water vapor, carbon monoxide,nitrogen oxide, nitrogen dioxide, and ozone, absorb heat from incomingsolar radiation but do not allow long-wave radiation to reflect backinto space. GHGs in the atmosphere result in the trapping of absorbedheat and warming of the earth's surface. In the U.S., GHG emissions comemostly from energy use driven largely by economic growth, fuel used forelectricity generation, and weather patterns affecting heating andcooling needs. Energy-related carbon dioxide emissions, resulting frompetroleum and natural gas, represent 82 percent of total U.S. human-madeGHG emissions. Another greenhouse gas, methane, comes from landfills,coal mines, oil and gas operations, and agriculture; it represents ninepercent of total emissions. Nitrous oxide (5 percent of totalemissions), meanwhile, is emitted from burning fossil fuels and throughthe use of certain fertilizers and industrial processes. World carbondioxide emissions are expected to increase by 1.9 percent annuallybetween 2001 and 2025. Much of the increase in these emissions isexpected to occur in the developing world where emerging economies, suchas China and India, fuel economic development with fossil energy.Developing countries' emissions are expected to grow above the worldaverage at 2.7 percent annually between 2001 and 2025; and surpassemissions of industrialized countries near 2018.

Landfills can also be significant sources of GHG emissions if no or poorlandfill gas connection system is in place, mostly because of methanereleased during decomposition of waste, such as, for example, municipalsolid waste (MSW). Compared with carbon dioxide, methane is twenty-onetimes stronger than carbon dioxide as a GHG. Today, landfills areresponsible for about 4% of the anthropogenic emissions. Considerablereductions in methane emissions can be achieved by combustion of wasteand by collecting methane from landfills. The methane collected from thelandfill can either be used directly in energy production or flared off,i.e., eliminated through combustion without energy production.Combustion Of Waste May Reduce Greenhouse Gas Emissions, Science Daily(Dec. 8, 2007).

One measure of the impact human activities have on the environment interms of the amount of green house gases produced is the carbonfootprint, measured in units of carbon dioxide (CO₂). The carbonfootprint can be seen as the total amount of carbon dioxide and otherGHGs emitted over the full life cycle of a product or service. Normally,a carbon footprint is usually expressed as a CO₂ equivalent (usually inkilograms or tons), which accounts for the same global warming effectsof different GHGs. Carbon footprints can be calculated using a LifeCycle Assessment method, or can be restricted to the immediatelyattributable emissions from energy use of fossil fuels.

An alternative definition of carbon footprint is the total amount of CO₂attributable to the actions of an individual (mainly through theirenergy use) over a period of one year. This definition underlies thepersonal carbon calculators. The term owes its origins to the idea thata footprint is what has been left behind as a result of the individual'sactivities. Carbon footprints can either consider only direct emissions(typically from energy used in the home and in transport, includingtravel by cars, airplanes, rail and other public transport), or can alsoinclude indirect emissions which include CO₂ emissions as a result ofgoods and services consumed, along with the concomitant waste produced.

The carbon footprint can be efficiently and effectively reduced byapplying the following steps: (i) life cycle assessment to accuratelydetermine the current carbon footprint; (ii) identification of hot-spotsin terms of energy consumption and associated CO₂-emissions; (iii)optimization of energy efficiency and, thus, reduction of CO₂-emissionsand reduction of other GHG emissions contributed from productionprocesses; and (iv) identification of solutions to neutralize the CO₂emissions that cannot be eliminated by energy saving measures. The laststep includes carbon offsetting, and investment in projects that aim atthe reducing CO₂ emissions.

The purchase of carbon offsets is another way to reduce a carbonfootprint. One carbon offset represents the reduction of one ton ofCO₂-eq. Companies that sell carbon offsets invest in projects such asrenewable energy research, agricultural and landfill gas capture, andtree-planting.

Purchase and withdrawal of emissions trading credits also occurs, whichcreates a connection between the voluntary and regulated carbon markets.Emissions trading schemes provide a financial incentive fororganizations and corporations to reduce their carbon footprint. Suchschemes exist under cap-and-trade systems, where the total carbonemissions for a particular country, region, or sector are capped at acertain value, and organizations are issued permits to emit a fractionof the total emissions. Organizations that emit less carbon than theiremission target can then sell their “excess” carbon emissions.

For many wastes, the disposed materials represent what is left overafter a long series of steps including: (i) extraction and processing ofraw materials; (ii) manufacture of products; (iii) transportation ofmaterials and products to markets; (iv) use by consumers; and (v) wastemanagement. At virtually every step along this “life cycle,” thepotential exists for GHG impacts. Waste management affects GHGs byaffecting energy consumption (specifically, combustion of fossil fuels)associated with making, transporting, using, and disposing the productor material that becomes a waste and emissions from the waste inlandfills where the waste is disposed.

Traditionally, attempts have been made to use various types ofincineration as means for reducing the amount, or volume, of materialswhich must be disposed of in landfills. However, only few have providedeconomically affordable improvements or effective solutions to the solidwaste problems. Of course, incineration, although reducing the volume ofwastes disposed of in landfills, creates a large GHG emission andthereby the carbon foot print of the disposed of product, now waste, isnot decreased. Various attempts have been made to utilize solid wastesdirectly, blended with other solid/liquid fuels, or after some form ofprocessing, as fuels for electric power generation. While some projectshave proven technically feasible, only a few have proven to be eitherenvironmentally desirable or economically attractive. Most waste energyrecovery projects cost the municipalities more than the originallandfills they replace, and do not represent substantial environmentalimprovements.

Incineration typically reduces the volume of the MSW by about 90% withthe remaining 10% of the volume of the original MSW often beinglandfilled. This incineration process produces large quantities of theGHG CO₂. Typically, the joules of energy produced per equivalents CO₂expelled during incineration are very low. Thus, incineration of MSW forenergy production releases GHG into the atmosphere with comparativelylittle energy return. Therefore, if GHGs are to be avoided, newsolutions for the disposal of wastes, such as MSW, other thanlandfilling and incineration, are needed.

Each material disposed of as waste has a different GHG impact dependingon how it is made and disposed. The most important GHGs for wastemanagement options are carbon dioxide, methane, nitrous oxide, andperfluorocarbons. Of these, carbon dioxide (CO₂) is by far the mostcommon GHG emitted in the US. Most carbon dioxide emissions result fromenergy use, particularly fossil fuel combustion. Carbon dioxide is thereference gas for measurement of the heat-trapping potential (also knownas global warming potential or GWP). By definition, the GWP of onekilogram (kg) of carbon dioxide is 1. Methane has a GWP of 21, meaningthat one kg of methane has the same heat-trapping potential as 21 kg ofCO₂. Nitrous oxide has a GWP of 310. Perfluorocarbons are the mostpotent GHGs with GWPs of 6,500 for CF₄ and 9,200 for C₂F₆. Emissions ofcarbon dioxide, methane, nitrous oxide, and perfluorocarbons are usuallyexpressed in “carbon equivalents.” Because CO₂ is 12/44 carbon byweight, one metric ton of CO₂ is equal to 12/44 or 0.27 metric tons ofcarbon equivalent (MTCE). The MTCE value for one metric ton of each ofthe other gases is determined by multiplying its GWP by a factor of12/44 (The Intergovernmental Panel on Climate Change (IPCC), ClimateChange 1995: The Science of Climate Change, 1996, p. 121). Methane(CH₄), a more potent GHG, is produced when organic waste decomposes inan oxygen free (anaerobic) environment, such as a landfill. Methane fromlandfills is the largest source of methane in the US.

Treatment methods for biodegradable waste—composting and digestionreduce the GHG emissions compared with landfilling. Biogas production ina digestion plant yields more emission reductions than composting, ifthe biogas can be utilized for production of heat, electricity, ortransportation fuel. The efficiency is even better if the separation ofwaste components takes place already at the source and if fossil fuelsare replaced by biogas.

The greater GHG emission reductions are usually obtained when recycledwaste materials are processed and used to replace fossil fuels. If thereplaced material is biotic (material derived from living organisms), itis not always possible to obtain reductions of emissions. Even otherfactors, such as the treatment of the waste material and the fate of theproducts after the use, affect the emission balance. For example, therecycling of oil-absorbing sheets made of recycled textiles lead toemission reductions compared with the use of virgin plastic. In anotherexample, the use of recycled plastic as raw material for constructionmaterial was found to be better than the use of impregnated wood. Thisis because the combustion of plastic causes more emissions thanimpregnated wood for reducing emissions. If the replaced material hadbeen fossil fuel-based, or concrete, or steel, the result would probablyhave been more favorable to the recycling of plastic.

Given the effect of GHGs on the environment, different levels ofgovernment are considering, and in some instances have initiated,programs aimed at reducing the GHGs released into the atmosphere duringthe conversion of fuels into energy. One such initiative is the RegionalGreenhouse Gas Initiative (RGGI). RGGI is a market-based programdesigned to reduce global warming pollution from electric power plantsin the Northeast. Other such initiatives are being considered indifferent sections of the U.S. and on the federal level. RGGI is agovernment mandated GHG trading system in the Northeastern U.S. Thisprogram will require, for example, that coal-fired power plantsaggressively reduce their GHG emissions by on average 2.5% per year. Oneway to do this is by changing the fuel source used or scrubbing theemissions to remove the pollutants. An alternative is to purchase carboncredits generated by others which can offset their emissions into theatmosphere.

Thus, there is a need for alternative fuels that burn efficiently andcleanly and that can be used for the production of energy and/or rawmaterials for the production of petrochemicals. There is, at the sametime, a need for waste management systems that implement methods forreducing GHG emissions of waste. In particular, there is a need forreducing the carbon foot print of materials by affecting their end-stagelife cycle management. By harnessing and using the energy contentcontained in waste, it is possible to reduce GHG emissions generatedduring the processing of wastes and effectively use the waste generatedby commercial and residential consumers.

It is therefore an object of this invention to provide an improved andeconomical process for the disposal of domestic waste by recovering theenergy and matter bound within it and reducing the need for fossilfuels. It is a further object of this invention to provide an improvedfeed stock for the control of the output from processes for theproduction of energy and/or production of raw materials forpetrochemical production. It is another object of this invention toprovide an improved feed stock for thermal-conversion ofcarbon-containing materials to obviate the disadvantages of prior artsystems.

It is also an object of this invention to provide an integrated bunkerstorage system for waste streams based on physical and/or chemicalproperties of waste that, when subject to chemical conversion, effectthe output from processes for the production of energy and/or productionof raw materials for petrochemical production. It is another object ofthis invention to provide an integrated bunker storage system for wastestreams based on the chemical content of the waste and based on the useof the waste as components for a blended feed stock in a chemicalconversion process. It is yet a further object of this invention toprovide an integrated bunker storage system for waste streams based onthe energy content of waste streams. It is a further object of thisinvention to provide a process for storing waste streams based on thedesired energy content in feed streams necessary to achieve optimumthermal-conversion.

SUMMARY OF THE INVENTION

The present invention provides integrated bunker storage systems forwaste streams based on the composition and characteristics of wastestreams. In particular, the present invention provides a process forgenerating individual waste streams based on a set of materialcharacteristics. According to the system and method of the presentinvention, individual waste streams from wastes stored in bunkers aremixed in a given feed ratio to generate a feed stock that will produce adesired output from a chemical conversion process, e.g., gasification.

Under one aspect of the invention, a systems includes a first bunker ofwaste constituents of a first type separated from a mixed municipalsolid waste stream and a second bunker of waste constituents of a secondtype separated from the mixed municipal solid waste stream. The wasteconstituents of the first type are differentiated from the wasteconstituents of the second type based on the chemical composition of thewaste constituents. The waste types are also differentiated based on howa blended feed stock comprising a combination of the waste constituentsfrom the first and second bunkers affects at least one of (i) a hydrogento carbon monoxide gas production ratio and (ii) a total quantity ofhydrogen and carbon monoxide produced by a gasification process whensaid blended feed stock is converted in said gasification process.

Under another aspect of the invention, a system includes a first bunkerof waste constituents of a first type separated from a solid wastestream and a second bunker of waste constituents of a second typeseparated from the solid waste stream. The waste constituents of thefirst type are differentiated from the waste constituents of the secondtype based on at least one of physical characteristics and chemicalcharacteristics of the waste constituents. The waste types are alsodifferentiated based on how a blended feed stock comprising acombination of the waste constituents from the first and second bunkersaffects an output of a chemical conversion process when said blendedfeed stock is converted in said chemical conversion process.

Under a further aspect of the invention, the solid waste streamcomprises mixed municipal solid waste. Under still another aspect of theinvention, the solid waste stream comprises a source segregated stream.Optionally, the source segregated stream can comprise recyclablematerials, and the source segregated stream can comprise recyclingresidue.

Under yet another aspect of the invention, the waste constituents of thefirst type comprise materials including one of high densitypolyethylene, low density polyethylene, polyethylene terepthalate,fibers, paper, newsprint, wood, and fats, oils, and greases (FOGs).Likewise, the waste constituents of the second type can differ from thatof the first type and comprise materials including one of high densitypolyethylene, low density polyethylene, polyethylene terepthalate,fibers, paper, newsprint, wood, and fats, oils, and greases (FOGs).

Under an aspect of the invention, the waste constituents of the firsttype are differentiated from the waste constituents of the second typebased on at least one of the carbon, hydrogen, oxygen, sulfur, nitrogen,chlorine, and ash content of the waste constituents. Under anotheraspsect of the invention, the waste constituents of the first type aredifferentiated from the waste constituents of the second type based onthe moisture content of the waste constituents.

Under a further aspect of the invention, a method includes providing afirst and second bunker and differentiating between mixed solid wasteconstituents of a first type and a second type based on at least one ofphysical characteristics and chemical characteristics of the wasteconstituents and based on how the waste constituents affect an output ofa chemical conversion process when the waste constituents of the firstand second types are combined into a blended feed stock for conversionin the chemical conversion process. The method also includes placing thewaste constituents of the first type into the first bunker and placingthe waste constituents of the second type into the second bunker.

Under still another aspect of the invention, the method includesblending waste constituents of the first type with waste constituents ofthe second type to form the blended feed stock. Optionally, the methodcan include densifying the blended feed stock.

Under an aspect of the invention, a method of producing an engineeredfeed stock of a desired chemical composition includes providing a firstbunker of waste constituents of a first type separated from a mixedsolid waste stream and providing a second bunker of waste constituentsof a second type separated from the mixed solid waste stream. The methodalso includes determining a chemical composition of the wasteconstituents of the first bunker and determining a chemical compositionof the waste constituents of the second bunker. The method furtherincludes determining a quantitative ratio between the waste constituentsof the first bunker and the waste constituents of the second bunkersthat, when the waste constituents are combined in the quantitativeratio, provides the engineered feed stock of the desired chemicalcomposition. The method also include mixing the waste constituents ofthe first bunker and the second bunker according to the quantitativeratio to provide the engineered feed stock of the desired chemicalcomposition.

Under a further aspect of the invention, at least one of determining achemical composition of the waste constituents of the first bunker anddetermining a chemical composition of the waste constituents of thesecond bunker is based on a collection of chemical compositioninformation associated with waste types commonly occurring in themunicipal solid waste stream. Optionally, the collection of chemicalcomposition information associated with waste types commonly occurringin the municipal solid waste stream can be a lookup table.

Under another aspect of the invention, optical sorters collect datapertaining to at least one of a volume and a weight of the wasteconstituents in at least one of the bunkers and/or mixed into a blendedfeed stock. Optionally, this data can be certified to a third party.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1a and FIG. 1b show an exemplary process for separating and sortingwaste material.

FIG. 2 shows an exemplary flow diagram for processing sorted andseparated waste as feed stock for gasification.

FIG. 3 shows a flow diagram for processing waste feeds from multiplesources.

FIG. 4 shows estimates of typical waste composition in communities inthe United States.

FIG. 5 illustrates effects of moisture on heating value of wastematerials.

FIG. 6 shows heating values of waste feed stocks.

FIG. 7 shows a flow diagram for processing waste feeds into ahomogeneous fuel having a desired energy content suitable forgasification.

DETAILED DESCRIPTION

Gasification is a thermochemical process that generates a gaseous, fuelrich product. Regardless of how the gasifier is designed, two processesmust take place in order to produce a useable fuel gas. In the firststage, pyrolysis releases the volatile components of the fuel attemperatures below 600° C. (1112° F.). The by-product of pyrolysis thatis not vaporized, typically called char, consists mainly of fixed carbonand ash. In the second gasification stage, the carbon remaining afterpyrolysis is either reacted with steam, hydrogen, air, or pure oxygen.Gasification with air results in a nitrogen-rich, low energy contentfuel gas. Gasification with pure oxygen results in a higher qualitymixture of carbon monoxide and hydrogen and virtually no nitrogen.Gasification with steam is more commonly called “reforming” and resultsin a hydrogen and carbon dioxide rich “synthesis” gas (syngas).Typically, the exothermic reaction between carbon and oxygen providesthe heat energy required to drive the pyrolysis and char gasificationreactions.

The basic gasification reactions that must be considered include:

-   -   1) C+1/2 O₂→CO −110.5 kJ/mol (exothermic)    -   2) C+H₂O→CO+H₂ +131 kJ/mol (endothermic)    -   3) C+CO₂→2CO +172 kJ/mol (endothermic)    -   4) C+2H₂→CH₄ −74 kJ/mol (exothermic)    -   5) CO+H₂0→CO₂+H₂ −41 kJ/mol (exothermic)    -   6) CO+3H₂→CH₄+H₂0 −205 kJ/mol (exothermic)

All of these reactions are reversible and their rates depend on reactionkinetics, which are functions of temperature, pressure and concentrationof reactants in the reactor. A potential source of feed stock forproducing syngas via gasification is waste. Gasification processdevolatilizes and gasifies solid or liquid hydrocarbons in waste, andconverts them into a low or medium energy content gas. Gasification hasseveral advantages over traditional combustion of waste. It takes placein a reducing environment that limits the formation of dioxins and ofSO_(X) and NO_(X). Furthermore, it requires just a fraction of thestoichiometric amount of oxygen necessary for combustion. As a result,the volume of process gas is low, requiring smaller and less expensivegas cleaning equipment, and heat exchanger devices. The lower gas volumealso means a higher partial pressure of contaminants in the off-gas,which favors more complete adsorption and particulate capture accordingto chemical thermodynamics: ΔG=−RTln(P₁/P₀). Finally, gasificationgenerates a fuel gas that can be integrated with combined cycleturbines, reciprocating engines and, potentially, with fuel cells thatconvert fuel energy to electricity more efficiently than conventionalsteam boilers.

Referring now to the drawings, and more particularly, to FIG. 1a andFIG. 1b , generally at 100, there is shown an exemplary process forseparating and sorting waste material to be used as feed stock forengineered fuels. The waste materials can be, for example, a mixed MSWstream, a source segregated stream (e.g., a stream of recyclablematerials segregated from non-recyclable materials at the waste source),and/or a recycling stream residue, that is, a stream of materialsremaining after some quantity of recyclable materials has been removedfrom a waste stream. Waste materials are brought into a large receptionarea by waste collection vehicles as either single stream or as multiplestreams. The waste streams may be bagged, unbagged, or construction anddemolition (C&D) stream. Unbagged waste materials include, for example,commingled waste material, single stream waste material and oldcorrugated cardboards (OCC). Waste materials are dumped on a tippingfloor 102 and are then pushed onto a conveyor by a payloader. In oneembodiment, unbagged waste materials are presorted by customers. Inanother embodiment, unbagged waste materials are presorted by collectionservice at customer sites. From tipping floor 102, unbagged wastematerials are transferred to presorting station 104 by the conveyor.Presorting station 104 sorts the unbagged waste material into largeferrous, large plastic (e.g., large hard plastics), and plastic filmsubstreams. Each of the sub streams from presorting station 104 isfurther subdivided into two streams 104 a and 104 b. Clean and sortedwaste materials from presorting station 104 are included in first stream104 a, and are then transferred to bunker 106. In one embodiment,bunkers 106 may include compartments designated for each of the materialin the first stream 104 a.

Sorted waste materials, including contaminants, from presorting station104 are diverted as second stream 104 b to OCC screen 114. OCC screen114 screens out, for example, paper, bags, and corrugated fiber fromstream 104 b. In one aspect of the present invention, OCC screen 114 isan OCC disc screen, which includes multiple discs that rotate andimpart, for example, a wavelike motion that causes larger object such asOCC to move upwards, away from the remainder of stream 104 b. In someembodiments, OCC screen 114 will be utilized to remove mixed and officepaper from OCC. OCC screen 114 can utilize, for example, serratedelliptical disks made out of ½-inch thick steel plate. The size of thedisks can be changed, and the space between disks or rows of disks canbe varied to adapt to the stream of waste materials. In one embodiment,OCC screen 114 includes three decks for removing OCC fibers, non-OCCfibers, and containers that are sized at about 8 inches by 12 inches.Negatively sorted OCC stream 114 a from OCC screen 114 are transferredto picking platform 118, where fiber shreds and trash are removed fromOCC stream 114 a. Fiber shreds, trash, and OCC from picking platform 118are then transferred to bunkers 120.

If the waste from tipping floor comprises bagged waste materials, theconveyor carries the bagged waste materials for bag breaking/splitting.Before transferring the material for bag splitting, the material may beweighed using a scale. A bag splitter 108 tears the bags open andtransfers the waste material to other units in the process forseparation and sorting. Each unit in the process removes a particulartype of material from the waste materials.

First, the material from bag breaker 108 are transferred to a stringerscreening unit 110. The stringer screening unit 110 removes long strands(e.g., threads, strings, wires, tapes, ropes, etc.) that could damagedownstream equipment. After removing strings, waste materials aretransferred to trommel 112, where oversized materials are removed toprevent damage of downstream sorting equipment. A trommel is a rotatingcylindrical screen that is inclined at a downward angle from ahorizontal axis. For example, the cylindrical screen may include 8 inchholes, which allows material that are less than 8 inches to fall throughwhile retaining material larger than 8 inches within the cylinder.Material is fed into a trommel at the elevated end, and separationoccurs while the material moves down the drum. The tumbling action ofthe trommel separates materials that may be attached to each other. Inone embodiment of the present invention, sorting process may berearranged such that bagged waste materials are directly fed into atrommel with picks. Trommel picks may be attached to the insides of thecylindrical screen, and may be used to gently open bags and thendisperse the material without resizing the material. Sorted wastematerials from the trommel are then passed through a stringer unit toremove the strings from the waste materials.

Negatively sorted stream 112 a (e.g., trommel overs greater than 8inches) from trommel screen 112 are mixed with unbagged waste materialsfrom tipping floor 102, and then provided as input to presorting station104. For example, negatively sorted stream 112 a may include materialsthat are greater than 8 inches and have high fiber content. Positivelysorted stream 112 a (e.g., trommel unders greater than 8 inches) fromtrommel screen 112 are mixed with positively sorted stream 114 b (e.g.,OCC screen unders) from OCC screen 114, and then provided as input todisc screen 116. Although not shown, an additional picking platform canbe provided after trommel screen 112 to remove waste items that areproblematic, or that can not be otherwise processed by process 100.

Disc screen 116 sorts containers from fibers in input stream 114 b, anddivides the sorted material into output streams 116 a-c. In oneembodiment, disc screen 116 is similar to OCC screen 114 but withsmaller gaps between the discs. For example, disc screen 116 may includediscs with gaps between them to allow container sizes smaller than about2.5 inches by 3 inches to fall through. In other embodiments, systemssuch as those disclosed in U.S. Provisional Patent Application No.61/098,525, filed Sep. 19, 2008, entitled System And Method For SortingOf Mixed Materials Using Air Currents, incorporated by reference herein,are used to sort containers from fibers or further separate paper and/orfibers from other materials. Specifically, air jets can be placedbeneath OCC screen 114 to remove paper and/or fibers from the balance ofthe stream. Output stream 116 a from disc screen and/or othercontainer/fiber separation devices is provided as input to overheadmagnet line 122. Output stream 116 a may include trommel unders, OCCscreen unders, majority of glass materials, and containers that fallthrough the gaps between the discs in disc screen 116.

Positively sorted output stream 116 a is provided as input to overheadmagnet line 122 to separate ferrous metals from output stream 116 a.Negatively sorted materials may be further divided into dual line outputstreams 116 b-c is also provided as input to overhead magnet line 122 toseparate ferrous metals from output stream 116 b. Output streams 116 a-creduce burden depth, increase recovery, and reduce contamination levels.Overhead magnet line 122 includes a belt magnet suspended above aconveyor to pick up ferrous materials and transfer them onto a conveyorwhich deposits the ferrous material to a ferrous storage bunker 124.Remaining waste stream of nonferrous material from overhead magnet line122 is split into substreams 122 a-b.

First substream 122 a may comprise bulk light materials, predominantlybroken particles of glass, and plastics and non-ferrous containers ofsize less than about 3 inches by 3 inches. Substream 122 a is providedas input to disc screen 126 to break and separate glass from plastics.In one embodiment, disc screen 126 separates particles less than ⅜inches from the substream 122 a. Separated glass particles from discscreen 126 are stored in bunker 128. Disc screen overs 126 a comprisingpredominantly plastics, and small amounts of glass and airborne enabledmaterial are provided as input to de-stoner 130 (e.g., vibrating airclassifier) for separating more dense material such as glass and theairborne enabled material from the plastics. The waste material travelsacross a vibrating screen of de-stoner 130 and denser material such asthe glass and the airborne enabled material fall through openings in thescreen while the remaining lighter material are maintained above thescreen by air supplied from a fan. Output stream 130 b comprisingseparated glass from de-stoner 130 are mixed with glass particles inoutput stream 126 b, and then transported to storage bunker 128. Outputstream 130 c comprising separated airborne enabled material fall fromde-stoner 130 are transported to storage bunker 132. Remaining outputstream 130 a from de-stoner 130 are provided as input to optical sorter146 (FIG. 1b ).

Second substream 122 b, comprising predominantly fiber and reducedlevels of plastics, is provided as input to optical sorter 134. Opticalsorter 134 is used to remove all plastics from fiber browns. Opticalsorter 134 shines light onto the conveyor, and a sensor detects thereflected light from plastic materials. Using this information, thesensor locates the plastic material, targets a jet of air to hit theplastic material at the location, and removes it from the conveyor. Inone embodiment, optical sorter 134 is capable of detecting plasticmaterials on an eight feet wide conveyor. Remaining stream from opticalsorter 134, predominantly comprising fibers, is divided into fiberbrowns and remaining fibers. Removed fiber browns are stored in bunker136, and the remaining fibers are provided as input to picking platform138, where browns, old newspaper (ONP), plastics and trash are removed.In one embodiment, remaining fibers are provided as dual line input topicking platform 138. Browns, ONP, and trash from picking platform 138are then transferred to bunkers 140.

Next, a cascading set of optical sorters are used to sort plastics ofdifferent colors and sizes. Sensors in these cascading set of opticalsorters are capable of identifying plastics of different colors andsizes. Ejected plastics larger than a predetermined size, from opticalsorter 134, are provided as input to optical sorter 142. For example,ejected plastics larger than 3 inches are provided as input to opticalsorter 142. Optical sorter 142 detects and removes high densitypolyethylene (HDPE) color plastics from stream. In one embodiment,optical sorter 142 is capable of detecting HDPE color on an eight feetwide conveyor. Output stream 142 a comprising ejected HDPE colorplastics are transferred to bunker 144 for storage. In the remainingplastics, optical sorter 142 detects plastics of a predetermined sizeand ejects the detected plastics in a downward trajectory. In oneexample, sorted plastics smaller than 3 inches are ejected in a downwardtrajectory. In another example, sorted plastics from about 3 inches toabout 7 inches are ejected in a downward trajectory. Output stream 1426comprising ejected plastics of the predetermined size are thentransported to bunker 160 for storage. All remaining plastics largerthan the predetermined size are provided as input to optical sorter 148.

Optical sorter 148 detects and removes polyethylene terepthalate (PET)plastics from stream. In one embodiment, optical sorter 148 is capableof detecting PET on an eight feet wide conveyor. Output stream 148 acomprising ejected PET plastics are transferred to bunker 150 forstorage. In the remaining plastics, optical sorter 148 detects plasticsof a predetermined size and ejects the detected plastics in a downwardtrajectory. In one example, sorted plastics smaller than 3 inches areejected in a downward trajectory. In another example, sorted plasticsfrom about 3 inches to about 7 inches are ejected in a downwardtrajectory. Output stream 148 a comprising ejected plastics of thepredetermined size are mixed with output stream 142 b, and thentransported to bunker 160 for storage. Remaining plastics larger thanthe predetermined size are provided as input to optical sorter 154.

Optical sorter 154 detects and removes all I-IDPE natural plastics fromstream. In one embodiment, optical sorter 154 is capable of detectingHDPE natural on an six feet wide conveyor. Output stream 154 acomprising ejected HDPE natural plastics are transferred to bunker 156for storage. In the remaining plastics, optical sorter 154 detectsplastics of a predetermined size and ejects the detected plastics in adownward trajectory. In one example, sorted plastics smaller than 3inches are ejected in a downward trajectory. In another example, sortedplastics from about 3 inches to about 7 inches are ejected in a downwardtrajectory. Output stream 154 b comprising ejected plastics of thepredetermined size are mixed with output stream 142 b, and thentransported to bunker 160 for storage.

Another set of cascading optical sorters are used to sort plastics ofdifferent colors and sizes from output stream 130 a from de-stoner 130.Optical sorter 146 detects and removes all high density polyethylene(HDPE) color plastics from output stream 130 c. In one embodiment,optical sorter 146 is capable of detecting HDPE color plastics on a fourfeet wide conveyor. Output stream 146 a comprising ejected HDPE colorplastics are mixed with output stream 142 a, which is then transferredto bunker 144 for storage. In the remaining plastics, optical sorter 146detects plastics of a predetermined size and ejects the detectedplastics in a downward trajectory. In one example, sorted plasticssmaller than 3 inches are ejected in a downward trajectory. In anotherexample, sorted plastics from about 3 inches to about 7 inches areejected in a downward trajectory. Output stream 146 b comprising ejectedplastics of the predetermined size are mixed with output stream 142 b,which is then transported to bunker 160 for storage. Output stream 146 ccomprising all remaining plastics larger than the predetermined size areprovided as input to optical sorter 152.

Optical sorter 152 detects and removes all high polyethyleneterepthalate (PET) plastics from output stream 146 c. In one embodiment,optical sorter 152 is capable of detecting PET on a four feet wideconveyor. Output stream 152 a comprising ejected PET plastics are mixedwith output stream 148 a, which is then transferred to bunker 150 forstorage. In the remaining plastics, optical sorter 152 detects plasticsof a predetermined size and ejects the detected plastics in a downwardtrajectory. In one example, sorted plastics smaller than 3 inches areejected in a downward trajectory. In another example, sorted plasticsfrom about 3 inches to about 7 inches are ejected in a downwardtrajectory. Output stream 152 b comprising ejected plastics of thepredetermined size are mixed with output stream 142 b, which is thentransported to bunker 160 for storage. Output stream 152 c comprisingall remaining plastics larger than the predetermined size are providedas input to optical sorter 158.

Optical sorter 158 detects and removes all high density polyethylene(HDPE) natural plastics from output stream 152 c. In one embodiment,optical sorter 158 is capable of detecting HDPE natural plastics on afour feet wide conveyor. Output stream 158 a comprising ejected HDPEnatural plastics are mixed with output stream 154 a, which is thentransferred to bunker 156 for storage. In the remaining plastics,optical sorter 158 detects plastics of a predetermined size and ejectsthe detected plastics in a downward trajectory. In one example, sortedplastics smaller than 3 inches are ejected in a downward trajectory. Inanother example, sorted plastics from about 3 inches to about 7 inchesare ejected in a downward trajectory. Output stream 158 b comprisingejected plastics of the predetermined size are re-sorted by mixing withoutput stream 130 c, which is then provided as input to optical sorter146. Output stream 158 c comprising all remaining plastics larger thanthe predetermined size are provided as input to eddy current separator162.

Eddy current separator 162 separates the non-ferrous metals from outputstream 158 c. An eddy current separator includes spinning magnets thateject non-ferrous metals—such as aluminum—off the conveyor. Theseparator injects the non-ferrous material with the same charge thatsmall magnets in the drum carry. Like charges repel, and the non-ferrousmaterial bounce off the magnets into a chute. Output stream 162 acomprising sorted non-ferrous material is transported to bunker 164 forstorage. Remaining materials from eddy current separator 166 aredisposed as residue in bunker 166. Although not shown, an additionalde-stoner, such as de-stoner 130, can be included after eddy currentseparator 166 to separate generally light material from generally heavymaterial. Also, the residue remaining after the various separationoperations can be recirculated through process 100 to increase theamount of material diverted to the bunkers. The techniques, devices, andsystems described in U.S. Provisional Patent Application No. 61/100,038,filed Sep. 25, 2008, entitled System And Method For Tagging Products ForUse In Identification Of The Components Therein, U.S. patent applicationSer. No. 11/883,758, filed May 27, 2008, entitled Systems And MethodsFor Sorting Recyclables At A Material Recovery Facility, U.S. patentapplication Ser. No. 11/487,372, filed Jul. 17, 2006, entitled SystemsAnd Methods For Sorting Recyclables At A Material Recovery Facility,U.S. patent application Ser. No. 11/106,634, filed Apr. 15, 2005,entitled Systems And Methods For Sorting, Collecting Data Pertaining ToAnd Certifying Recyclables At A Material Recovery Facility, now U.S.Pat. No. 7,341,156, issued Mar. 11, 2008, U.S. patent application Ser.No. 11/802,497, filed May 23, 2007, entitled Systems And Methods ForOptimizing A Single-Stream Materials Recovery Facility, all incorporatedby reference herein, can be used in addition to or in combination withthe sorting and separation techniques set forth above.

Depending on market needs and economics, sorted material in each bunkerdiscussed above are either baled for resale to recycling facilities, ormay be further processed as engineered feed stock to produce fuel.Sorted wastes may generally be classified as fibers, plastics,fats/oils/grease (FOG), and sludge. Each of these class of sorted wastesmay be used to produce engineered feed stock having a predeterminedcomposition to achieve a desired output from a chemical conversionoperation. As used herein, desired outputs can include one or manyaspects of the product of the chemical conversion operation. Forexample, desired outputs include, but are not limited to, total quantityof material produced by the operation, the quantity of a particularmaterial present in the entire output from the operation, the ratio ofparticular materials produced by the operation, the quantity of certainimpurities in the entire output from the operation, and the higherheating value of the material produced by the operation.

As set forth above, a gasification unit can advantageously utilizevarious engineered feed stocks. Thus, for illustrative purposes, anembodiment of the invention employing gasification as the chemicalconversion operation is described below. However, other chemicalconversion operations are understood to be within the scope of theinvention. Engineered feed stock may then be, for example, used in thegasification unit to convert the feed stock into synthesis gas (syngas).Syngas may then be used in boilers to produce steam to run turbines ormaybe used in Fischer-Tropsch process to produce fuel.

FIG. 2, generally at 200, shows an exemplary flow diagram for processingsorted and separated waste as feed stock for gasification. At step 204,each type of waste withdrawn from bunkers 202 are weighed, and itsmoisture content measured by a moisture sensor 206. For example, feedmoisture content may be determined using an infrared detector or amicrowave detector. Control unit 208 receives information regarding themoisture content from moisture sensor 206 for each type of waste, andthen adjusts the withdrawal rate of the waste accordingly. Control unit208 specifies the quantity and type of waste to be withdrawn based on apredetermined recipe, which, in turn, is based on the chemical andphysical characteristics of the various types of waste. For example, theheating value and/or the chemical composition of the type of waste canbe taken into account. Thus, the absolute elemental (e.g., carbon,hydrogen, sulfur, and/or nitrogen) content of the waste, as well asratios of particular compounds or elements present in the waste, can beused to determine the quantity and type of waste to be withdrawn. Afterweighing the withdrawn waste at step 204, the wastes are transferred tovessel 210 for mixing and drying. For example, mixing in vessel 210 isperformed by an auger. In one aspect of the present invention, wasteheat from either gasifier 222 or Fischer-Tropsch equipment 230 may beused for drying waste in vessel 210. Using moisture information receivedfrom moisture sensor 206, control unit 208 determines amount of wasteheat needed to adjust the moisture content in the waste mixture invessel 210. Control unit 208 redirects waste heat either from gasifier224 or from Fischer-Tropsch equipment 230 to vessel 210 until a desiredmoisture content is reached.

Mixed and moisture adjusted waste material from vessel 210 istransferred to shredder 212. Shredder 212 shreds the waste material toobtain a predetermined size corresponding to a desired gasifier output.The desired gasifier output is determined by control unit 208, andshredding rate in shredder 212 is adjusted by the control unit 208.Control unit 208 can also take into account the cost of shredding thewaste material, as decreases in shred size can result in higheroperational costs. Based on feed stock requirements to gasifier, controlunit 208 determines at step 214 whether to convert shredded waste topellets. If control unit 208 determines not to convert shredded waste topellets, shredded waste is fed to waste feeder 216. Waste feeder 216processes shredded waste into densified feed stock with the optimumcharacteristics to achieve the desired gasifier output values, and feedsthe densified waste directly into gasifier 222. Waste feeder 216provides a process to drive densified wastes into a reactor vessel (anytype) that requires temperature or pressure differentials to bemaintained for the reactor to perform at optimal levels. This processwill also allow the reactor to receive a uniform rate of feed stock intothe reactor. The process has minimal mechanical moving parts and takesadvantage of waste properties to seal the reactor.

Moreover, an engineered feed stock not only provides the ability toachieve desired gasifier outputs, but the engineered feed stock alsoenables an otherwise heterogeneous collection of waste to be used asthough the waste were homogeneous. The deconstruction and reconstructionof the waste into engineered feed stock does not change theheterogeneous nature of the waste, rather, embodiments of the inventionmake the resultant engineered feed stock consistent. Such consistencyprovides for increased controllability of the gasification process.Without engineered feed stock, a gasification operation may experienceunpredictable variations in output as the characteristics of the reactorfeed change. The engineered feed stock reduces this variability of thewaste feed, thereby adding to the stability of the reaction feed system.Thus, embodiments of the invention enable precise levels of mixing ofvarious solid wastes and liquids to optimize discharge characteristicsrequired for optimal reaction and fuel requirements. Moreover,embodiments of the invention enable the creation of engineered feedstocks having chemical compositions that do not occur in nature, therebyreducing undesirable effects that occur with the gasification of naturalfuels, e.g., the formation of SO_(X) and NO_(X).

If control unit 208 determines that shredded waste are to be convertedto pellets, then shredded waste from shredder 212 is transferred topelletizer 218. Pelletizer 218 converts shredded waste to pelletscapable of undergoing pyrolysis at a predetermined rate. In oneimplementation, a Lundell 850 densifier (available from LundellManufacturing Company, Inc., of Cherokee, Iowa) can be used aspelletizer 218. The Lundell densifier can produce a pellet of about 2inches to about 6 inches in length and having a bulk density of about 45lb/ft′ to about 60 lb/ft³. Other methods of densification can be used inplace of pelletizer 218, which can produce pellets having greater orlesser length and greater or lesser bulk density and remain within thescope of the invention. Moreover, the techniques, devices, and systemsdescribed in U.S. patent application Ser. No. 12/492,093, filed Jun. 25,2009, entitled Engineered Fuel Pellet Useful For Displacement Of Coal InCoal Firing Plants, U.S. patent application Ser. No. 12/492,096, filedJun. 25, 2009, entitled Engineered Fuel Feed Stock, all incorporated byreference herein, can be used in addition or in combination with thepelletizing techniques set forth above. Pellets from pelletizer 218 arefed into gasifier 222 based on a feedrate requirement determined bycontrol unit 208. Excess pellets from pelletizer 218 are modified toinclude identifiers, and then transferred to bunker 220 for storage.

Pellets fed into gasifier 222 undergo pyrolytic conversion to syngas.Infrared detector 224 determines the composition of syngas and transfersthe information to control unit 208. Composition information frominfrared detector 224 is used by control unit 208 to adjust withdrawalrate of wastes from bunkers 202, and adjust moisture content in wastemixture to obtain the desired gasification outputs. The feedrate intogasifier 222 can also be determined, at least in part, by the rate ofconsumption of the pellets, e.g., the feedrate may be controlled inorder to maintain a steady level of material in gasifier 222. Syngasproduced by gasifier 222 may either be used in boilers 226 to producesteam to run turbines 232, or be used in Fischer-Tropsch process 230 toproduce fuel.

FIG. 3, generally at 300, shows an exemplary method of processingdifferent waste types stored in bunkers to generate feed stocks suitablefor gasification and having a particular composition and characteristicsto achieve a desired gasifier output, e.g., a gas of given energycontent, a specified molar ratio of carbon to hydrogen content, and/orother characteristics as set forth herein. FIG. 3 also illustrates amethod of adjusting the quantity of each type of waste to be combinedinto a feed stock based on the desired composition and characteristicsof the feed stock to achieve the desired gasifier output, e.g., syngasenergy content, syngas hydrogen to carbon monoxide ratio, and/or totalhydrogen and carbon monoxide production rate. Waste that is sorted intofibers, plastics, FOG, and sludge and stored in bunkers 202 may containcomponents of different compositions and moisture content. Further, thecomingled waste can be sorted into specific types of waste other thanthose illustrated in FIG. 3, .e.g., paper, newsprint, magazines,specific plastic types, textiles, yard waste, and rubber. Thecomposition and moisture content of each type of waste can vary based ontheir source and time of year, but the overall differences are notsubstantial. FIG. 4 shows estimates of the typical MSW composition incommunities in the United States. In particular, FIG. 4 illustrates thattotal MSW Generation in communities in the United States beforerecycling is equal to 246 million tons.

Heat content of raw waste depends on the concentration of combustibleorganic materials in the waste and its ash and moisture content.Similarly, different types of waste have different chemicalcompositions. Table 1 shows exemplary data on the combustiblecomposition of waste.

TABLE 1 Percent by weight (dry basis) Component Carbon Hydrogen OxygenNitrogen Sulfur Ash Organic Food wastes 48.0 6.4 37.6 2.6 0.4 5.0 Paper43.5 6.0 44.0 0.3 0.2 6.0 Cardboard 44.0 5.9 44.6 0.3 0.2 5.0 Plastics60.0 7.2 22.8 — — 10.0 Textiles 55.0 6.6 31.2 4.6  0.15 2.5 Rubber 78.010.0 — 2.0 — 10.0 Leather 60.0 8.0 11.6 10.0 0.4 10.0 Yard wastes 47.86.0 38.0 3.4 0.3 4.5 Wood 49.5 6.0 42.7 0.2 0.1 1.5 Inorganic Glass 0.50.1 0.4 <0.1 — 98.9 Metals 4.5 0.6 4.3 <0.1 — 90.5 Dirt, ash, 26.3 3.02.0 0.5 0.2 68.0 etc.

At step 302, compositions of each waste component are determined.Exemplary methods of determining the compositions include thermogravimetric analysis, Prompt Gamma Neutron Activation Analysis (PGNAA),Dual-Energy Gamma Attenuation, and the like. Feed composition can alsobe determined from a lookup table (for example, Table 1). Next, themoisture content in each type of waste is measured at step 304. In oneembodiment, moisture content is determined using an infrared detector.In another embodiment, moisture content is determined using a microwavedetector. Once the moisture content and compositions are determined, thecomposition and characteristics of each type of waste is determined atstep 306. An exemplary method of calculating the energy content of thewaste types includes calorimetry. The energy content can be expressed inkJ per kilogram (kJ/kg).

The techniques, devices, and systems described in U.S. Pat. No.7,341,156, incorporated above, can be used in conjunction with variouslookup tables and/or other sources of composition data to determineoverall feed composition. That patent discloses techniques forseparating various types of comingled waste using optical sortingdevices. In addition, optical composition recorders and controllers areused to collect and accumulate data on the type, volume, and quality ofthe various types of waste that are processed, e.g., paper and plastic.Thus, as the optical sorters and composition recorders process a mixedstream of MSW, the controllers amass data representative of the quantityand quality of certain materials in a particular bunker. Thisinformation and the information in the lookup tables is then used todetermine an average composition of the material presently stored in aparticular bunker. This composition information can then be used, as setforth below, to determine how much material from a particular bunker isneeded to form a feed stock of a desired composition.

For example, different types of plastics have different chemicalcompositions, e.g., the chemical formula for PET monomer is C₁₀H₈O₄,while the chemical formula for LDPE monomer is C₂H₄, and those materialshave different energy content. Thus, as a sorting process (such as theembodiments set forth above) diverts items of different plastic types toa single bunker, the ratio of carbon to hydrogen, in the aggregate,changes as the different items are added to the bunker. Likewise, theaggregate energy content changes as different items are added. Thetechniques set forth above enable the determination of the aggregatecomposition and energy content of the material in each bunker. Thus, asthe plastic materials of different types are all diverted to a plasticmaterial bunker, the controllers take the quantity and particular typeof plastic into account in determining the overall composition andenergy content of the material in the bunker. This aggregate compositioninformation can then be used, as set forth below, to determine thequantity of mixed plastic to use in order to achieve a feed stock ofdesired composition. As described herein, the control of feed stockcomposition and characteristics is not limited carbon to hydrogen ratioand energy content, but can include, and is not limited to, totalhydrogen and carbon monoxide production, total contaminate content,total pollutant content, content of a particular compound, ashcharacteristics, etc.

At step 308, a feed ratio is set based on the overall characteristics,including composition, of each type of waste, and the overall desiredcharacteristics corresponding to the final feed stock ratio iscalculated at step 310. At step 312, the method determines whether thecalculated characteristics are equal to the desired characteristicsneeded to achieve the desired gasification outputs. If at step 312 themethod determines that the calculated characteristics equal the desiredcharacteristics needed for gasification, then at step 316, the wastetypes are mixed according the feed ratio set at step 310. If at step 312the method determines that the calculated characteristics are not equalto the desired characteristics needed for gasification, then at step314, the feed ratio is adjusted until the calculated characteristicscorrespond to the desired characteristics of feed required by thegasification unit. Although not shown, the mixed waste types can bedensified, such as in a pelletizer, as set forth above.

The disclosure herein, in combination with techniques, devices, andsystems described in U.S. Pat. No. 7,341,156, incorporated above, alsoenable the data regarding the final composition of the engineered feedstock to be certified, which can then be provided to a third party. Asset forth above, the aggregate composition of the material in aparticular bunker can be determined using, for example, the opticalsorters and composition recorders. As each type of waste from thebunkers is combined according to a known feed ratio, the finalcomposition of the engineered feed stock is known. Thus, an operator ofthe systems described herein can certify the composition of theengineered feed stock to a third party, such as a syngas producer,electrical power producer, and/ other party using the engineered feedstock. Moreover, the contents of each bunker can be similarly certified.Such a certification enables third parties to improve the control ofchemical conversion processes that consume the engineered feed stocks byproviding information about the composition and characteristics of thefeed stocks prior to their use. In addition, the certification data canbe used to establish pricing for the various engineered feed stocks andto facilitate calculation of feed stock generation and usage on avolumetric and/or weight basis.

Because the physical characteristics and chemical composition of aparticular feed stock is known, the techniques set forth herein alsoenable the feed stocks to be classified and ranked relative to eachother. Thus, the feed stock could be ranked and classified according tothe energy content of the feed stocks that is released duringcombustion. Likewise, the feed stocks could be ranked on the basis ofvarious pollutants that are generated during combustion or gasification.Further still, existing classification methods could be applied to thefeed stocks to obtain comparative data. For example, the Parr formulasused to classify and rank coal can be applied to the feed stocks,thereby enabling the estimation of certain properties associatedtherewith. The Parr formulas are set forth in Equations 1-3.

$\begin{matrix}{F^{\prime} = \frac{100( {F - {0.15S}} )}{100 - ( {M + {1.08A} + {0.55S}} )}} & {{Equation}\mspace{14mu} 1} \\{V^{\prime} = {100 - F^{\prime}}} & {{Equation}\mspace{14mu} 2} \\{Q^{\prime} = \frac{100( {Q - {50S}} )}{100 - ( {M + {1.08A} + {0.55S}} )}} & {{Equation}\mspace{14mu} 3}\end{matrix}$where:

-   -   M=wt % moisture (moist basis)    -   F=wt % fixed carbon (moist basis)    -   A=wt % ash (moist basis)    -   S=wt % sulfur (moist basis)    -   Q=BTU/lb (moist basis)    -   F′=wt % fixed carbon (dry basis)    -   V′=wt % volatile matter (dry basis)    -   Q′=wt % BTU/lb (dry basis)

In one embodiment of the present invention, it is desirous to produce anengineered feed stock of relatively high energy content. In such anembodiment, the feeds of waste are further mixed with at least onecomponent that contributes to increasing the energy content of theoverall feed stock. In another embodiment of the present invention, theoverall feed stock energy content is adjusted by decreasing the moisturecontent of at least one component of the feed. For example, on average,raw MSW has an energy content of roughly 13,000 kJ/kg or about half thatof bituminous coal, and the moisture content of raw MSW is 20% onaverage. FIG. 5 shows an exemplary illustration of how the energycontent of MSW and its components change with moisture content. Pointsshown are experimental values, and solid lines show the thermochemicalcalculations for various organic compounds. FIG. 5 shows that mixedplastics and rubber contribute the highest energy content to municipalsolid waste. Moist food and yard wastes have the lowest energy contentand are better suited for composting, rather than for combustion orgasification.

FIG. 6 shows exemplary energy content of various materials, includingraw MSW. Based on the thermodynamic properties of the combustiblecomponents of municipal solid waste, the following are exemplarymolecular formulas for the key components of MSW:

-   -   Mixed paper: C₆H_(9.6)O_(4.6)N_(0.036) S_(0.01)    -   Mixed plastics: C₆H_(18.6)O_(1.7)    -   Mixed food wastes: C₆H_(9.6)O_(3.5)N_(0.28) S_(0.2)    -   Yard wastes: C₆H_(9.2)O_(3.8)N_(0.01)S_(0.04)

The hydrocarbon formula that most closely approximates the mix oforganic wastes in MSW is C₆H₁₀O₄.

Ash composition and concentration of a fuel can result in agglomerationin a gasification vessel leading to clogging of gasifiers and increasedtar formation. In general, slagging does not occur with fuels having anash content below 5%. MSW has high ash content (10-12%), versus coal ash(5-10%) and wood wastes (1-5% ash). Raw MSW can be converted into abetter fuel for power generation by making it more homogeneous.

FIG. 7 illustrates an exemplary method 700 of processing waste typesreceived from various sources on different days into a homogeneous fuelhaving a desired energy content suitable for gasification to produce afuel gas. At step 702, each waste type is withdrawn from bunkers 202based on a feed ratio, as determined at step 310 in FIG. 3. Withdrawnwaste types can be reduced in size by a shredder, as set forth above. Atstep 704, shredded wastes are mixed into a homogeneous mixture. At step706, energy content in the mixed feed is calculated based on the feedratio and energy content of the feed components. At step 708, calculatedenergy content is compared with the desired energy content of feed stockfor gasification. If the energy content of the mixed feed does not equalthe desired energy content, then at step 710, feed ratio of the wastetypes is adjusted based on the deviation of mixed feed energy contentfrom desired energy content.

If the energy content of the mixed waste types equals the desired energycontent, then at step 712, mixed waste is densified for optimumvolatilization during gasification. In one embodiment of the presentinvention, the mixed feed is densified (e.g., into pellets) to achieve ahigher density feed. This, in turn, can increase the capacity of thegasifier and/or aid in reducing the required residence time in thegasification reactor, thereby allowing for complete conversion. Table 2illustrates exemplary specifications of a MSW feed for a gasificationsystem. In one implementation of the present invention, the mixed wastefeed stock is densified into pellets. While a range of values forthermal diffusivity is provided, this characteristic can be outside ofthe range stated when pelletized feed stock has sufficient porosity.

TABLE 2 Diameter 0.635 cm to 7.62 cm Length 1.27 cm to 15.24 cm BulkDensity 160 kg/m³ to 1202 kg/m³ Surface to Volume 20:1 to 3:1 Porosity0.4 to 0.6 Aspect Ratio 1 to 10 Thermal Conductivity 0.04 W/mK to 1.0W/mK Specific Heat Capacity 0.2 J/kgK to 2 J/kgK Thermal Diffusivity 1 ×10⁻⁶ m²/s to 2 × 10⁻⁵ m²/s Net Calorific Value 6,900 kJ/kg to 35,000kJ/kg Moisture 5-25% Volatile Matter 40% to 80% Fixed Carbon 5% to 20%Carbon 30% to 80% Sulfur <1% Chlorine <0.5% Ash <10%

At step 718, the densified feed stock undergoes gasification. During andafter gasification of densified feed, the energy content of syngasgenerated is determined at step 720. Calculated syngas energy contentfrom step 720 is compared with the desired energy content for the syngasat step 722. If the energy content generated is less than the desiredenergy content, then at step 724, the deviation from the desired energycontent is calculated. At step 716, the method determines whether thedeviation from the desired energy content is greater than apredetermined threshold value. For example, the threshold value may varyfrom about 5% to about 20%. If the deviation from the desired value isgreater than a predetermined threshold value, then at step 710 feedratios of waste types are adjusted using this deviation. New waste typesare withdrawn at step 702 using this adjusted feed ratio from step 710.If the deviation is less than a predetermined threshold value, then atstep 714, energy content of mixed feed is adjusted by addition ofadditives. Exemplary additives include fats, oils, grease, yard waste,sludge, glycerin, tires, crumb rubber, petroleum waste, and the like. Inone embodiment of the present invention, if the deviation is less thanby at least 10%, feed rates of densified feed (e.g., pellets) into thegasification reactor is adjusted based on the measured deviation ofenergy content. If at step 722 the calculated syngas energy content fromstep 720 is determined to be equal to the desired energy content, thenat step 726, the syngas is processed further to generate fuel. As setforth above, manipulating feed stock composition and characteristics tocontrol for energy content is merely an illustrative example of oneembodiment of the invention. Other characteristics of the mixed feedstock can be manipulate to control for other desired gasifier outputs.These desired outputs can include, but are not limited to, carbonmonoxide to hydrogen ratio in syngas production, low contaminate contentin syngas production, and/or overall syngas production.

Aspects of method 700 can be modified to achieve homogeneous feed stockhaving a chemical composition suitable for gasification to produce asyngas of a desired composition. As set forth above, the aggregatechemical composition of the material in a particular bunker can bedetermined. Thus, rather than controlling for energy content, method 700controls for aggregate chemical composition of the mixture in order toachieve a feed stock that produces a syngas of desired composition whenthe feed stock is gasified. Further still, the methods set forth hereincan produce a feed stock with a particular composition andcharacteristics so as to produce a desired output from another type ofchemical conversion. For example, a feed stock yielding a relativelyhigh amount of heat when burned, while emitting a relatively low amountof pollutants (e.g., SON, NON, chlorine, etc.) can be produced. In suchan implementation, certain chemical compounds (e.g., CaO, ZnO, etc.) canbe added at step 714 to react in-situ with potential pollutants in thefeed stock mixture.

The following tables provide illustrative examples of engineered feedstocks that have been created using the techniques described herein. Thefollowing are examples only, and other feed stocks, composed of otherwaste types and having different compositions, are within the scope ofthe invention. In addition to the physical characteristics and chemicalcomposition of the engineered feed stocks, the tables provide thequantitative ratios, e.g., weight percentage, volumetric percentage,etc., of particular types of waste that were blended to produce theparticular feed stock. For example, feed stock #1 was produced from 82wt % newsprints and 18 wt % plastics—thus, the quantitative ratio is 82parts newsprints to 18 parts plastics. In the tables below, the data inthe column labeled “AR” represents the composition as received by agasification process (set forth in more detail below), and the data inthe column labeled “MF” represents a moisture free composition.

The illustrative feed stocks were gasified, and the output results wereobtained. This information is also included in the tables below. Thefeed stocks were gasified using the following procedure. Gasificationtests were performed at a laboratory scale stratified downdraftgasifier. The gasifier has an inside diameter of 6 inches and a heightof 24 inches above a perforated grate. There are four Type-Kthermocouples installed along the gasifier, 1″, 7″, 19″ above the grateand 4″ below the grate. The real-time temperatures are recorded by adata logger thermometer (OMEGA, HH309A). A syngas sampling train,consisting of two water scrubbers, and a vacuum pump is used for takingsyngas samples, which is analyzed by a HP5890A gas chromatograph toobtain volumetric fractions of H2, N2, CO, CO2 and CH4. A dry gas testmeter is installed in the air entrance to measure the air intake rate.As shown in the tables below, the output from the gasifier can beaffected by manipulating the types of waste that are blended into thefeed stock to be processed by the gasifier.

TABLE 3 Feed stock #1 FS#1 82 wt % Newsprints, 18 wt % Plastics AR MFMoisture, wt % 3.25 Ash, wt % 4.51 4.66 Volatile, wt % 86.43 89.33 FixedCarbon, wt % 5.81 6.01 Sulfur, WT % 0 0.01 Hydrogen, wt % 7.57 7.82Carbon, wt % 51.88 53.62 Nitrogen, wt % 0.06 0.06 Oxygen, wt % 32.6533.75 Carbon/Hydrogen 6.9 6.9 Carbon/Oxygen 1.6 1.6 HHV (BTU/lb) 9,5529,873 HHV (BTU/lb), Calculated 10,696 Density (lb/cu. Ft) 20.3

TABLE 4 Feed stock #1 Gasifier Output Hydrogen, vol % 14.9 Nitrogen, vol% 51.6 Carbon Monoxide, vol % 18.9 Methane, vol % 2.3 Carbon Dioxide,vol % 12.3 Hydrogen/Carbon Monoxide 0.79 BTU/scf 134.79 CarbonMonoxide + Hydrogen 33.8

TABLE 5 Feed stock #2 FS#2 36 wt % Magazines, 64 wt % Plastics AR MFMoisture, wt % 0.94 Ash, wt % 6.53 6.59 Volatile, wt % 92.48 93.36 FixedCarbon, wt % 0.05 0.05 Sulfur, wt % 0.05 0.01 Hydrogen, wt % 9.51 9.60Carbon, wt % 68.85 69.50 Nitrogen, wt % 0.01 0.01 Oxygen, wt % 14.1214.25 Carbon/Hydrogen 7.2 7.2 Carbon/Oxygen 4.9 4.9 HHV (BTU/lb) 13,99114,124 HHV (BTU/lb), Calculated 15,064 Density (lb/cu. Ft)

TABLE 6 Feed stock #2 Gasifier Output Hydrogen, vol % 21.9 Nitrogen, vol% 45.6 Carbon Monoxide, vol % 18.9 Methane, vol % 6.4 Carbon Dioxide,vol % 7.3 Hydrogen/Carbon Monoxide 1.16 BTU/scf 200.21 Carbon Monoxide +Hydrogen 40.8

TABLE 7 Feed stock #3 FS#3 24.5 wt % Other Papers, 75.5 wt % Textiles ARMF Moisture, wt % 1.57 Ash, wt % 7.57 7.69 Volatile, wt % 75.12 76.32Fixed Carbon, wt % 15.74 15.99 Sulfur, wt % 0.37 0.01 Hydrogen, wt %5.85 5.94 Carbon, wt % 48.12 48.89 Nitrogen, wt % 8.38 8.51 Oxygen, wt %28.14 28.59 Chlorine, wt % 3.44 3.49 Carbon/Hydrogen 8.2 8.2Carbon/Oxygen 1.7 1.7 HHV (BTU/lb) 9,629 9,783 HHV (BTU/lb), Calculated8,705 Density (lb/cu. ft) 21.9

TABLE 8 Feed stock #3 Gasifier Output Hydrogen, vol % 6.5 Nitrogen, vol% 64.6 Carbon Monoxide, vol % 19.3 Methane, vol % 0.3 Carbon Dioxide,vol % 9.3 Hydrogen/Carbon Monoxide 0.3 BTU/scf 88.6 Carbon Monoxide +Hydrogen 25.7

TABLE 9 Feed stock #4 FS#4 91.8 wt % Newsprint, 2.2 wt % Plastics, 6.0wt % Yard wastes AR MF Moisture, wt % 3.64 Ash, wt % 9.62 9.98 Volatile,wt % 77.26 80.18 Fixed Carbon, wt % 9.48 9.84 Sulfur, wt % 0.08 0.01Hydrogen, wt % 5.45 5.66 Carbon, wt % 41.81 43.39 Nitrogen, wt % 0.070.07 Oxygen, wt % 39.33 40.82 Carbon/Hydrogen 7.7 7.7 Carbon/Oxygen 1.11.1 HHV (BTU/lb) 7,296 7,572 HHV (BTU/lb), Calculated 7,520 Density(lb/cu. Ft) 33.7

TABLE 10 Feed stock #4 Gasifier Output Hydrogen, vol % 19.8 Nitrogen,vol % 46.4 Carbon Monoxide, vol % 24.7 Methane, vol % 1.2 CarbonDioxide, vol % 8.0 Hydrogen/Carbon Monoxide 0.80 BTU/scf 159.2 CarbonMonoxide + Hydrogen 44.5

TABLE 11 Feed stock #5 FS#5 68 wt % paper, 32 wt % Rubber AR MFMoisture, wt % 1.35 Ash, wt % 9.11 9.23 Volatile, wt % 77.18 78.24 FixedCarbon, wt % 12.36 12.53 Sulfur, wt % 0.23 0.01 Hydrogen, wt % 5.84 5.92Carbon, wt % 45.92 46.55 Nitrogen, wt % 0.01 0.01 Oxygen, wt % 37.5538.06 Chlorine, wt % 0.219 0.22 Carbon/Hydrogen 7.9 7.9 Carbon/Oxygen1.2 1.2 HHV (BTU/lb) 9,250 9,377 HHV (BTU/lb), Calculated 8,288 Density(lb/cu. Ft)

TABLE 12 Feed stock #5 Gasifier Output Hydrogen, vol % 14.9 Nitrogen,vol % 51.6 Carbon Monoxide, vol % 17.0 Methane, vol % 3.4 CarbonDioxide, vol % 13.1 Hydrogen/Carbon Monoxide 0.88 BTU/scf 140.56 CarbonMonoxide + Hydrogen 31.8

TABLE 13 Feed stock #6 FS#6 100 wt % Rubber AR MF Moisture, wt % 0.06Ash, wt % 6.12 6.12 Volatile, wt % 68.46 68.50 Fixed Carbon, wt % 25.3625.38 Sulfur, wt % 1.92 0.01 Hydrogen, wt % 6.78 6.78 Carbon, wt % 81.7381.78 Nitrogen, wt % 0.18 0.18 Oxygen, wt % 3.21 3.21 Carbon/Hydrogen12.1 12.1 Carbon/Oxygen 25.5 25.5 HHV (BTU/lb) 15,780 15,789 HHV(BTU/lb), Calculated 15,768 Density (lb/cu. Ft) 28.6

TABLE 14 Feed stock #6 Gasifier Output Hydrogen, vol % 8.65 Nitrogen,vol % 68.2 Carbon Monoxide, vol % 14.5 Methane, vol % 0.71 CarbonDioxide, vol % 6.9 Hydrogen/Carbon Monoxide 0.60 BTU/scf 83.7 CarbonMonoxide + Hydrogen 23.2

TABLE 15 Feed stock #7 FS#7 80 wt % Rubber, 20 wt % Paper + water to 13wt % AR MF Moisture, wt % 13.1 Ash, wt % 3.84 4.42 Volatile, wt % 61.9471.28 Fixed Carbon, wt % 21.12 24.30 Sulfur, wt % 1.28 0.01 Hydrogen, wt% 5.87 6.75 Carbon, wt % 75.12 86.44 Nitrogen, wt % 0.03 0.03 Oxygen, wt% 0.77 0.89 Chlorine, wt % 0.076 0.09 Carbon/Hydrogen 12.8 12.8Carbon/Oxygen 97.6 97.6 HHV (BTU/lb) 14,405 16,577 HHV (BTU/lb),Calculated 16,574 Density (lb/cu. ft)

TABLE 16 Feed stock #7 Gasifier Output Hydrogen, vol % 28.6 Nitrogen,vol % 45.2 Carbon Monoxide, vol % 15.6 Methane, vol % 2.7 CarbonDioxide, vol % 7.9 Hydrogen/Carbon Monoxide 1.83 BTU/scf 173.8 CarbonMonoxide + Hydrogen 44.2

TABLE 17 Feed stock #8 FS#8 100 wt % dry rubber (Signature PremiumRubber Mulch) AR MF Moisture, wt % 0.84 Ash, wt % 4.51 4.55 Volatile, wt% 69.32 69.91 Fixed Carbon, wt % 25.33 25.54 Sulfur, wt % 1.62 0.01Hydrogen, wt % 7.08 7.14 Carbon, wt % 85.37 86.09 Nitrogen, wt % 0.150.15 Oxygen, wt % 0.43 0.43 Carbon/Hydrogen 12.1 12.1 Carbon/Oxygen198.5 198.5 HHV (BTU/lb) 16,331 16,469 HHV (BTU/lb), Calculated 16,765Density (lb/cu. ft) 21.4

It is thought that the integrated waste storage system and method of thepresent invention and many of its attendant advantages will beunderstood from the foregoing description and it will be apparent thatvarious changes may be made in the form, construction arrangement ofparts thereof without departing from the spirit and scope of theinvention or sacrificing all of its material advantages, the formhereinbefore described being merely a preferred or exemplary embodimentthereof.

What is claimed is:
 1. A method of producing an engineered feed stock ofa desired chemical composition, the method comprising: providing a firstbunker of waste constituents of a first type comprising predominatelyplastic materials separated from a mixed solid waste stream; providing asecond bunker of waste constituents of a second type comprisingpredominately fiber materials separated from the mixed solid wastestream; determining an elemental chemical composition of the wasteconstituents of the first bunker including at least one of a carboncontent (wt %), a hydrogen content (wt %), and oxygen content (wt %);determining an elemental chemical composition of the waste constituentsof the second bunker including at least one of a carbon content (wt %),a hydrogen content (wt %), and oxygen content (wt %); determining aquantitative ratio based on at least one of a carbon content (wt %), ahydrogen content (wt %), and oxygen content (wt %), between the wasteconstituents of the first bunker and the waste constituents of thesecond bunker that, when the waste constituents of the first bunker andthe waste constituents of the second bunker are combined in thequantitative ratio, provides the engineered feed stock of the desiredelemental chemical composition; and mixing the waste constituents of thefirst bunker and the second bunker according to the quantitative ratiobased on at least one of a carbon content (wt %), a hydrogen content (wt%), and oxygen content (wt %)to provide the engineered feed stock of thedesired elemental chemical composition.
 2. The method of claim 1,wherein the mixed solid waste stream comprises municipal solid waste. 3.The method of claim 1, wherein the mixed solid waste stream comprises asource segregated stream.
 4. The method of claim 3, wherein the sourcesegregated stream comprises recyclable materials.
 5. The method of claim3, wherein the source segregated stream comprises recycling residue. 6.The method of claim 1, further comprising forming the mixed wasteconstituents into a densified feed stock.
 7. The method of claim 1,wherein at least one of determining a chemical composition of the wasteconstituents of the first bunker and determining a chemical compositionof the waste constituents of the second bunker is based on a collectionof chemical composition information associated with waste types commonlyoccurring in the municipal solid waste stream.
 8. The method of claim 7,wherein the collection of chemical composition information associatedwith waste types occurring in the municipal solid waste stream is alookup table.
 9. The method of claim 7, further comprising collectingdata pertaining to a chemical composition of the mixed wasteconstituents of the first bunker and the second bunker.
 10. The methodof claim 9, wherein the data is certified for use by a third party. 11.The method of claim 1, further comprising combining the mixed wasteconstituents with an additive.
 12. The method of claim 11, wherein theadditive is at least one of a fat, oil, and grease.
 13. The method ofclaim 11, wherein the additive is at least one of yard wastes andsludge.
 14. The method of claim 11, wherein the additive is at least oneof tires and crumb rubber.
 15. The method of claim 11, wherein theadditive is petroleum waste.
 16. The method of claim 1, wherein thesecond bunker of waste constituents consists essentially of newsprintmaterials, the first bunker of waste constituents consists essentiallyof plastic materials, and the quantitative ratio is about 82 parts ofwaste constituents of the second bunker to about 18 parts of wasteconstituents of the first bunker.
 17. The method of claim 1, wherein thesecond bunker of waste constituents consists essentially of magazinematerials, the first bunker of waste constituents consists essentiallyof plastic materials, and the quantitative ratio is about 36 parts ofwaste constituents of the second bunker to about 64 parts of wasteconstituents of the first bunker.
 18. The method of claim 1, wherein thesecond bunker of waste constituents consists essentially of papermaterials, the first bunker of waste constituents consists essentiallyof textile materials, and the quantitative ratio is about 24.5 parts ofwaste constituents of the second bunker to about 75.5 parts of wasteconstituents of the first bunker.
 19. The method of claim 1, wherein thesecond bunker of waste constituents consists essentially of newsprintmaterials, the first bunker of waste constituents consists essentiallyof plastic materials, and the quantitative ratio is about 91.8 parts ofwaste constituents of the second bunker to about 2.2 parts of wasteconstituents of the first bunker, and the method further comprisingcombining the mixed waste constituents with 6.0 parts yard wastes. 20.The method of claim 1, wherein the second bunker of waste constituentsconsists essentially of paper materials, the first bunker of wasteconstituents consists essentially of rubber materials, and thequantitative ratio is about 68.0 parts of waste constituents of thesecond bunker to about 32.0 parts of waste constituents of the firstbunker.
 21. The method of claim 1, wherein the first bunker of wasteconstituents consists essentially of rubber materials, the second bunkerof waste constituents consists essentially of paper materials, and thequantitative ratio is about 80.0 parts of waste constituents of thefirst bunker to about 20.0 parts of waste constituents of the secondbunker, and the method further comprising combining the mixed wasteconstituents with 13.0 parts water.
 22. The method of claim 1, whereindetermining the chemical composition of the waste constituents of thefirst bunker and/or determining the chemical composition of the wasteconstituents of the second bunker includes a measurement using thermogravimetric analysis, prompt gamma neutron activation analysis (PGNAA),and/or dual-energy gamma attenuation.